Immutable collections

This project contains immutable collections that can be used in older Java projects.

Usage

No maven or gradle configuration! Just copy the needed source files into your project.

Collections

ImmutableList

Implements a decorator for Lists which is immutable.

Creation

Use on of these factory methods:

    List<String> fromSingleItems = ImmutableList.of("A", "B", "C");
    List<String> fromArray = ImmutableList.of(new String[]{"A", "B", "C"});

For Streams you can collect the items:

    List<String> collectedFromStream = Stream.of("A", "B", "C")
            .collect(ImmutableList.collect());

ImmutableMap

Implements a decorator for Maps which is immutable.

Creation

    Map<String, String> fromEntries = ImmutableMap.of(
            ImmutableMap.entry("1", "A"),
            ImmutableMap.entry("2", "B"),
            ImmutableMap.entry("3", "C")
    );

    Map<String, String> fromMap = ImmutableList.of(new HashMap<>());

For Streams you can collect the items:

    Map<String, String> collectedMap = yourStream
            .collect(
                    ImmutableMap.collect(
                            <keyMapperFunction>,
                            <valueMapperFunction>
                    )
            );

ImmutableSet

Implements a decorator for Sets which is immutable.

Creation

Use on of these factory methods:

    Set<String> fromSingleItems = ImmutableSet.of("A", "B", "C");
    Set<String> fromArray = ImmutableSet.of(new String[]{"A", "B", "C"});    

From Collection, Iterable or Iterator:

    Collection<String> collection = ImmutableList.of("A", "B", "C");
    Set<String> fromCollection = ImmutableSet.of(collection);

    Iterable<String> iterable = ImmutableList.of("A", "B", "C");
    Set<String> fromIterable = ImmutableSet.of(iterable);

    Set<String> fromIterator = ImmutableSet.of(collection.iterator());

For Streams you can collect the items:

    Set<String> collectedFromStream = Stream.of("A", "B", "C")
            .collect(ImmutableSet.collect());